Method and system of modulation classification using signal graphs

This invention relates system for classifying a modulation format of a communication signal. The system includes a receiving antenna system, to receive the communication signal, a 5 preprocessing module, to evaluate a Fourier transform of a plurality of samples of the received communication signal, normalize each discrete sample of the Fourier transform, quantize each normalized sample based on a number of quantization levels (Q), a graphical analyzer to construct a undirected graph by tracing amplitude of the each quantized sample; and a classification module to extract one or more modulation classification (MC) features from the .0 undirected graph; and to determine the modulation format of the received communication signal based on the extracted MC features. Receive a communication signal modulated by a modulation format ., 602 Evaluate a Fourier transform of a plurality of samples of the received communication signal Normalize each discrete sample of the Fourier transform Quantize each normalized sample based on a number of quantization levels (Q) lConstruct a undirected graph by tracing amplitude of the each quantized sample I\ Extract one or more modulation classification (MC) features from the undirected graphs Determine the modulation format of the received communication signal based on the extracted MC features